Original Article
Clinical outcomes in hybrid repair procedures for pathologies involving the aortic arch
Vascular 2015, Vol. 23(1) 9–16 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1708538114525608 vas.sagepub.com
Sebastian Zerwes1, Giesbert Leissner2, Yvonne Gosslau1, Rudolf Jakob1, Hans-Kees Bruijnen1, Frank Oertl3 and Klaus Woelfle1
Abstract Objective: Fifty patients with complex aortic disease, who received hybrid treatment of the aortic arch with supraaortic debranching and endovascular stent-graft repair, were evaluated in regard to events of primary (survival and technical success) and secondary (procedure-related complications) interest. Methods: The single-center study was conducted over an eight-year period from December 2004 to December 2012. Treated medical conditions included 23 aortic aneurysms (46%), 21 aortic dissections (42%), and six penetrating aortic ulcers (12%). Procedures were divided into groups of elective, urgent, and emergent. Results: Twenty-eight (56%) patients were operated electively, 15 (30%) urgently, and seven (14%) emergently. Sternotomy, cardiopulmonary bypass, and deep hypothermic circulatory arrest were required in 12 (24%) patients. The primary technical success rate was 86% and raised to 92% (n ¼ 46) of secondary technical success rate after therapy of three type I endoleaks. The 30-day mortality added up to 16.0%, and the mean time of survival was 49.3 months. In a total of eight (16%) patients, an endoleak occurred (five endoleaks type I, three endoleaks type II), while nine (18%) of patients suffered a perioperative stroke. Conclusions: In severely ill patients with complex aortic diseases, hybrid therapy may offer a promising alternative to conventional open repair.
Keywords Hybrid repair, aortic arch, debranching, clinical results, stroke, aortic dissection
Introduction The treatment of pathologies of the aortic arch remains to be a major challenge. Due to the fact that the open replacement of the aortic arch still requires hypothermic cardiac arrest, this procedure is affiliated with high rates of mortality and morbidity.1–3 Recently, so-called hybrid repair procedures have been pushed into the foreground as a therapeutic alternative to open repair. Those procedures seem to promise a less invasive treatment, as they combine less burdensome extra-anatomical bypasses with thoracic endovascular aortic repair (TEVAR), hence allowing for aortic arch repair in patients who are suboptimal candidates for open surgery. Since pathologies of the aortic arch are relatively rare, it is only now that results from larger studies and even systematic reviews of clinical outcomes in hybrid procedures are being published.4 However, randomized
study results, guidelines, and recommendations by societies of vascular surgery are still to be accomplished. The goal of the present study was the evaluation of the clinical outcomes in 50 patients who received hybrid repair of the aortic arch. In this study, the events of primary interest were survival and technical success; the events of secondary interest were procedure-related complications. 1
Department of Vascular surgery, Klinikum Augsburg, Germany Department of Radiology, Klinikum Augsburg, Germany 3 Department of Cardiac surgery, Klinikum Augsburg, Germany 2
Corresponding author: Sebastian Zerwes, Department of Vascular surgery, Klinikum Augsburg, Germany. Email: [email protected]
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Methods Patient population The study represents a case series study with retrospective analysis of prospectively collected non-randomized data. The single-center study was conducted at Klinikum Augsburg over an eight-year period from December 2004 to December 2012 and enrolled 50 patients with hybrid repair of complex aortic disease. The criteria for patient selection were based upon the comorbidities, and hence risk of surgery, of the patients, as well as the particular anatomy of the aortic arch. Treated medical conditions included 23 aortic aneurysms (46%; average aneurysm diameter 60 mm; three aneurysms associated with lusorian artery aneurysms), 21 aortic dissections (42%; thereof six (12%) Stanford type A and 15 (30%) Stanford type B), and six penetrating aortic ulcers (12%). Out of the 50 patients included in this study, 28 (56%) were operated electively, 15 (30%) urgently, and 7 (14%) emergently.
Procedural approach Preoperatively, all patients received a computed tomography (CT) scan of the aorta including supra-aortic
branches (0.75 mm collimation, recon layer thickness 1 mm). Subsequently, all images were digitally reconstructed (image processing) and the size of the stentgraft to be applied was measured using the program 3mensio Medical Imaging (3mensio Medical Imaging B.V., Bilthoven, the Netherlands). In order to assess the individual risk of surgery, all secondary diagnoses were gathered and can be found together with the demographic data in Table 1. As far as permitted by the case status, the patients received a lung function test, an evaluation of the pump function of the left ventricle using echocardiography, as well as a sonographic assessment of the carotid and subclavian arteries. Whether a procedure was performed single or double stage was individually decided within the multidisciplinary board, consisting of vascular and cardiac surgeons, as well as interventional radiologists. Among the factors taken into consideration were the age of the patient, comorbidities, size of the aneurysm, as well as the risk of rupture of the aneurysm. Dissection-related procedures were mostly performed single stage in order to control symptoms of organ hypoperfusion or other life-threatening conditions. All surgical interventions were carried out in operating rooms (ORs) equipped with a C-arm X-ray unit (Philips Pulsera, screen diagonal 31 cm). All procedures were performed under general anesthesia.
Table 1. Demographics, comorbidities and principal diagnoses.
Age Male gender History of tobacco use Diabetes Hypertension Hyperlipidemia COPD Renal insufficiency Myocardial infarction Coronary artery disease History of stroke History of TIA Abdominal aneurysm Abdominal aneurysm surgery Ascending aortic surgery Principal diagnosis Aneurysm Dissection Penetrating aortic ulcer
Total (n ¼ 50)
Elective (n ¼ 28)
Urgent (n ¼ 15)
69 36 (72%) 6 (12%) 8 (16%) 38 (76%) 18 (36%) 4 (8%) 19 (38%) 5 (10%) 11 (22%) 5 (10%) 3 (6%) 6 (12%) 4 (8%) 10 (20%)
66 18 (64%) 4 (14%) 5 (18%) 19 (68%) 10 (36%) 4 (14%) 11 (39%) 3 (11%) 6 (21%) 3 (11%) 2 (7%) 5 (18%) 4 (14%) 5 (18%)
76 12 (80%) 1 (7%) 2 (13%) 14 (93%) 5 (33%) 0 4 (27%) 1 (7%) 4 (27%) 1 (7%) 1 (7%) 0 0 3 (20%)
2
23 (46%) 21 (42%) 6 (12%)
18 (64%) 7 (25%) 3 (11%)
3 (20%) 10 (67%) 2 (13%)
2 (29%) 4 (57%) 1 (14%)
COPD: chronic obstructive pulmonary disease; TIA: transient ischemic attack.
Emergent (n ¼ 7)
6 1 1 5 3 4 1 1 1 1
p
72 (86%) (14%) (14%) (71%) (43%) 0 (57%) (14%) (14%) (14%) 0 (14%) 0 (29%)
0.85 >0.99 0.19 >0.99 0.25 0.4 >0.99 0.89 >0.99 >0.99 0.20 0.25 0.30
}
0.03
Zerwes et al. During all cases that took place in cooperation with cardiac surgery, near-infrared spectroscopy was used to monitor cerebral perfusion. In regard to the proximal landing zone, we required at least 20 mm of healthy aorta, in order to be able to safely deploy the stent-graft. Stent placement was either performed retrogradely via a femoral/iliac conduit access, or antegradely through the ascending aorta. In order to ensure central positioning, the unfolding of the stent-graft took place in short apnea and controlled hypotension. Additionally, adenosine-induced cardiac arrest was conducted for the proximal landing zones 0 and 1, to allow for undisturbed stent-graftrelease without the pulsatile pressure of the antegrade blood flow. All patients received a first postoperative CT-scan control; if possible, follow-up CT-scan controls (CT serial imaging) were performed after 6, 12, 24, and 36 months.
Definition of events of primary and secondary interest Events of primary and secondary interest were defined as proposed by the guidelines for endovascular procedures by the AdHoc Committee.5 Technical success was defined as successful aortic debranching combined with a stent-graft placement with secure proximal and distal anchorage, without the need of conversion to open surgery. The event ‘‘stroke’’ was defined as the continued existence of neurologic symptoms for over 24 h. Events of primary interest in our study were technical success, as well as survival of the patient. Events of secondary interest were determined as procedural complications (endoleaks, peripheral embolization, etc.).
Statistical analysis All patients who underwent diagnostic measures that required a patient consent also agreed that the collected data may be used for study purposes. All data were collected using a Microsoft Excel 2007 database. To statistically analyze the collected data, the program Statsdirect Version 2.7.8 (StatsDirect Ltd, Cheshire, UK) was applied. The comparison of dichotomous variables was performed through calculation of odds ratios. Nominal variables with multiple characteristics were analyzed with a contingency table using the Fisher–Freeman–Halton exact test. Due to the small number of patients, there was no sufficient data to perform a multivariate analysis in regard to the endpoint ‘‘perioperative stroke.’’
11
Results Patient demographics and surgical procedures As indicated by the p values in Table 1, no significant differences of distribution in regard to the case status were found. However, the distribution of principal diagnosis was significant in regard to case status, as the majority of elective cases were aneurysms, while the majority of urgent and emergent cases were dissections. Penetrating ulcers were equally distributed among the groups. The median ASA score was 3 (range 2–4); 64% (n ¼ 32) of the procedures were performed single stage, 36% (n ¼ 18) double stage. Tables 2 and 3 display the implemented debranching techniques and the distribution of proximal landing zones according to the internationally used Ishimaru classification.6 We considered all debranchings involving a frozen elephant trunk as proximal landing zone 3, since the stent-graft is anatomically located in said zone. Table 4 provides detailed information about the procedures that were carried out in cooperation with cardiac surgeons. All said procedures involved at least the revascularization of the innominate artery and the left common carotid artery. In 43 (86%), a transfemoral access was used for stent placement, one (2%) were delivered via an iliac conduit, and 6 (12%) were delivered antegradely through the ascending aorta. The antegrade approach was only chosen when the femoral vessels were unsuitable as access-side due to massive calcification or if the iliac vessels showed extreme kinking, hence making it difficult to deliver a stent-graft. An average of 1.5 stent-grafts was implanted (range 1–4 stent-grafts). We used stent-grafts by GORE (n ¼ 4), Medtronic (n ¼ 15), Jotec (n ¼ 9), Cook (n ¼ 10), and Le Maitre (n ¼ 42). The median stent diameter was 36.5 mm, and the median length of the stented distance was 200 mm. Forty-four percent of cases (n ¼ 22) were performed in cooperation with cardiac surgeons.
Table 2. Debranching. Complete debranching (revascularization of IA, LCCA and LSA) Revascularization of IA and LCCA Revascularization of LCCA and LSA Revascularization of LCCA Revascularization LSA
6 16 11 6 11
IA: innominate artery; LCCA: left common carotid artery; LSA: left subclavian artery.
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Vascular 23(1) Table 3. Proximal landing zones. Proximal landing zone
Total (n ¼ 50)
Elective (n ¼ 28)
Urgent (n ¼ 15)
Emergent (n ¼ 7)
p
0 1 2 3
18 (36%) 17 (34%) 11 (22%) 4 (8%)
9 9 7 3
4 (27%) 6 (40%) 4 (27%) 1 (7%)
5 (71%) 2 (29%) 0 0
0.34
(32%) (32%) (25%) (11%)
}
Table 4. Procedures performed in cooperation with cardiac surgeons. #
Sex
Case status
Procedure
CPB
Cerebral perfusion
1 2
m m
Elective Elective
þ
Direct selective antegrade
3 4 5 6
m f f f
Elective Elective Elective Elective
7 8
m m
Urgent Emergent
9
m
Urgent
10 11
f m
Elective Elective
12 13
m f
Urgent Elective
14 15 16
f m m
Elective Urgent Emergent
17 18 19 20 21 22
m m f m m f
Urgent Elective Elective Emergent Emergent Emergent
Revascularization of IA and LCCA Revascularization of IA and LCCA, FET, aortic valve repair Revascularization of IA and LCCA, FET Revascularization of IA and LCCA Revascularization of IA and LCCA Revascularization of IA and LCCA, replacement of ascending aorta and aortic arch (partial) Revascularization of IA and LCCA, FET Revascularization of IA and LCCA, replacement of ascending aorta and aortic arch (partial) Revascularization of IA and LCCA, replacement of ascending aorta and aortic arch (partial) Revascularization of IA and LCCA Revascularization of IA and LCCA, aortic valve repair, replacement of ascending aorta Revascularization of IA and LCCA Revascularization of IA and LCCA, replacement of ascending aorta Revascularization of IA and LCCA, FET Revascularization of IA and LCCA , CABG Revascularization of IA and LCCA, replacement of ascending aorta Complete debranching Complete debranching Complete debranching, CABG Complete debranching Complete debranching Complete debranching, aortic valve repair, replacement of ascending aorta and aortic arch (partial)
þ þ
Direct selective antegrade
þ þ
None Direct selective antegrade
þ
Direct selective antegrade
Direct selective antegrade
þ
None
þ þ þ
Axillary antegrade selective Axillary antegrade selective Axillary antegrade selective
þ þ
Axillary antegrade selective
Axillary antegrade selective
CABG: coronary artery bypass graft; CBP: cardio pulmonary bypass; f: female; FET: frozen elephant trunk; IA: innominate artery; LCCA: left common carotid artery; m: male.
Technical success In our study, eight patients (16%) suffered from endoleaks type I or II (5), one (2%) from intraoperative death, and one (2%) died within 24 h of surgery. No
conversion to open surgery, stent fracture, or stent migration occurred. Hence, the primary technical success rate was 86% and raised to 92% after successful therapy of three endoleaks.
Zerwes et al.
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Table 5. Postoperative outcomes: technical success and complications.
Primary technical success Secondary technical success Endoleak Type 1/thereof treated Endoleak Type 2/thereof treated Intraoperative death 30-day mortality Stroke Paraplegia Late-onset endoleak Clotting of debranching bypass Peripheral embolization Stent-associated hemorrhage
Total (n ¼ 50)
Elective (n ¼ 28)
Urgent (n ¼ 15)
Emergent (n ¼ 7)
p
43 (86%) 46 (92%) 5/3 (10%/6%) 3/1 (6%/2%) 1 (2%) 8 (16%) 9 (18%) 1 (2%) 0 3 (6%) 1 (2%) 1 (2%)
26 (93%) 27 (96%) 1/1 (4%/4%) 3/1 (11%/4%) 0 3 (11%) 5 (18%) 1 (4%) 0 2 (7%) 1 (4%) 1 (4%)
11 (73%) 12 (80%) 3/1 (20%/7%) 0/0 0 3 (20%) 4 (27%) 0 0 1 (7%) 0 0
5 (71%) 6 (86%) 1/1 (14%/14%) 0/0 1 (14%) 2 (29%) 0 0 0 0 0 0
0.15 0.15 0.15 0.71 0.14 0.43 0.45 >0.99 >0.99 >0.99 >0.99
Survival Taking into account the one intraoperative death and the one death within 24 h of surgery, 30-day mortality added up to 16% (n ¼ 8). Further details can be found in Table 5. The mean time of follow-up was 49 months (maximum 62 months), while the Kaplan–Meier estimates for survival after 1, 6, 12, 24, and 60 months were 84%, 81%, 81%, 70%, and 70%, respectively (Figure 1).
Complications An overview of all complications is shown in Table 5.
Endoleaks As stated above, a total of eight (16%) endoleaks was found in the first postoperative CT-scan control, five (10%) of which were endoleaks type I, while three (6%) corresponded to endoleaks type II. In the endoleak type I group, three of the five endoleaks were treated. Thereof two were endoleaks type Ia and received interventional coiling, while one was an endoleak type Ib and was treated by a stent extension. The remaining two endoleaks were only observed due to limited treatment options in regard to vascular anatomy. However, in the following CT controls, one had not increase in size, while the other had even regressed in size. In the endoleak type II group, one of three endoleaks was treated by interventional coiling of the lusorian artery. The remaining two endoleaks were only observed: One declined over the course of observation spontaneously, the other one did not show any progression of size during follow-up.
Figure 1. Survival analysis (including patients at risk) using the Kaplan–Meier-method.
Clotting of the debranching bypass Three patients (6%) suffered from clotting of the carotid–subclavian bypass. Thereof two were treated with a bypass revision due to stroke. The third patient did not receive a revision of the clotted bypass since he was neurologically stabile.
Cerebral and spinal complications A total of nine patients (18%) suffered an ischemic stroke, of which two (4%) were embolic, while seven (14%) were due to hypoperfusion. No intracranial hemorrhage occurred. The three (6%) patients with clotting of the debranching bypass were all among the seven (14%) strokes due to hypoperfusion. In the group of embolic strokes, a CT scan confirmed cerebral
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Table 6. Predictive factors for stroke (univariate analysis: odds ratio).
Risk factor Debranching including reinsertion of at least IA and LCCA LSA covered and not revascularized Involvement of cardiac surgery required CPB Age > median Renal insufficiency
Odds ratio (95% confidence interval) 1.02 (0,24–4,37) 3.13 1.02 1.55 1.31 0.78
(0,68–14,31) (0,24–4,37) (0,33–7,37) (0,30–5,60) (0,17–3,58)
CPB: cardio pulmonary bypass; IA: innominate artery; LCCA: left common carotid artery; LSA: left subclavian artery.
initial renal function, while the other two (2%) died from cerebral complications. One patient, who underwent tracheotomy during her intensive care unit stay, developed an infection of the debranching bypass of both carotids: She was conservatively treated with vacuum seal therapy and antibiotics and fully recovered. One patient with an acute aortic dissection hemorrhaged perioperatively due to an aortic wall erosion caused by baresprings of the stent. The baresprings of the proximal end of the stent-graft had caused bleeding of the aortic wall in the region of the anastomosis of the debranching bypass graft. The patient died shortly after surgery.
Hypoperfusion of the left arm Table 7. Predictive factors for stroke (univariate analysis: Fisher-Freeman-Halton exact). Risk factor Urgency (elective-urgent-emergent) Diagnosis (aneurysm-dissection-PAU) Covered aortic zones including zone 0–4 (Ishimaru)
Fisher–Freeman– Halton exact 0.45 0.6 0.06
PAU: penetrating aortic ulcer.
embolisms. Tables 6 and 7 show the univariate analysis of predictive factors for stroke. One patient suffered from spinal cord ischemia, which manifested itself as a paralysis of the left leg and vertigo. Since both symptoms improved during the in-hospital stay, the patient did not receive an additional intervention.
Peripheral embolization and other complications One patient (2%) developed multiple peripheral embolizations leading to right leg ischemia, embolic small bowl ischemia, and multiple organ infarctions (liver, kidney, and spleen), which lead to the patient’s death four days postoperatively. Two patients (4%) suffered from a myocardial infarction postoperatively, one of whom subsequently was treated with coronary artery bypass grafts. The other patient developed a pericardial effusion which was drained operatively. One patient (2%) experienced a multiorgan failure with respiratory insufficiency, leading to the patient’s death. Acute renal failure occurred in four patients (8%). Thereof two (2%) fully recovered and regained their
None of the 28 (56%) patients who received a revascularization of the left subclavian artery developed a symptomatic hypoperfusion of the left arm. Out of the 22 (44%) patients who did not get their subclavian artery revascularized, one (2%) patient developed a steal syndrome, while another one suffered from a symptomatic hypoperfusion of the left arm.
Discussion Although open surgical repair is considered by many as the treatment of choice for pathologies involving the aortic arch in low-risk patients, such invasive surgery is associated with significant in-hospital mortality rates as reported by many studies.1–3 In comparison, hybrid repair of the aortic arch with supra-aortic debranching prior to stent-graft deployment has the advantage of providing reduced invasiveness and hence accomplishing an opportunity to operate on patients otherwise deemed unfit for surgery. Nevertheless, apart from the remaining difficulties with the application of endovascular devices in this anatomically challenging area, this relatively new technique still requires validation as a treatment option.4,7 The present study reports our outcomes of 50 patients who underwent hybrid repair. Taking into account previously published studies, it represents a rather large series.4 The majority of our cohort were high-risk patients with significant co-morbidities. For instance, 13 (26%) of patients had had previous cardiac or vascular surgery, 42 (84%) had one or more cardiac risk factors, and eight (16%) had had a neurologic event. In addition, the involvement of the cardiac surgery department was needed in 22 (44%) cases, which makes a comparison of outcomes of other studies, which tend to have lower cardiac surgery participation, difficult.
Zerwes et al.
Stent-associated complications The most common stent-associated complications were endoleaks. The majority of studies incorporate only the occurrence of endoleaks type I and III, which require primary therapy and are important for technical success. The incidence of endoleaks varies from 0 to 30%, with some authors reporting increased rates of endoleaks the more central the proximal landing zones and the more stents being used.5,6,8 In the present study, we detected in the first postoperative control in 5 (10%) an endoleak type I, thereof 3 (6%) were treated. All treated endoleaks were eliminated. No endoleaks type III occurred; furthermore, no late-onset endoleaks were observed. Compared to the results of other reports, the number of endoleaks in the present study is relatively small. One of our strategies to avoid endoleaks was to create an adequate proximal landing zone of at least 20 mm, as postulated by many other authors.9,10 Using an average landing zone of 38 mm, Gelpi et al. report an endoleak rate of 0%. In order to achieve that, they favor a complete debranching.8 Whether the benefits of a low endoleaks rate outweigh the surgical risks of complete debranching seems at least worthy of discussion. Despite a low incidence of endoleaks for total debranching, Melissano et al.9 reported an increased risk for neurologic complications. We consider a proximal landing of 20 mm to be sufficient, since acceptable rates of endoleaks can be accomplished while avoiding the risks of complete debranching. Regular CT-scan controls warrant adequate safety. In the early phase of our study, one patient with an acute aortic dissection hemorrhaged perioperatively due to an aortic wall erosion caused by baresprings of the stent. As described before, the baresprings of the proximal end of the stent-graft had caused bleeding of the aortic wall in the region of the anastomosis of the debranching bypass graft. While this stent with baresprings was certainly not the best therapeutic option for this patient, it was the only one at hand at that time. Tadakoshi et al.11 describe a similar case in which the baresprings also caused bleeding of the aortic wall. We stopped using stents with baresprings in zones close to debranching bypasses ever since.
Neurologic complications Ischemic stroke is an important complication after TEVAR. The more central the pathology of the thoracic aorta, the higher the risk of stroke.12,13 Overall, the present study showed an increased rate of strokes, which affected 9 (18%) of patients. Other studies report perioperative stroke rates after hybrid repair, ranging from 0.8% to 25.0% with a pooled event ratio of 6.9%.4 In our study, two-thirds of the strokes affected the first half of the patient population, while only one-third of the
15 strokes affected the latter cohort. Thus, the rate of strokes declined over the course of time. While this is concurrent with the findings of Cao et al.4, stating that an increased caseload lowered the risk of neurologic complications, this effect is influenced by different factors. When we noticed the high rate of strokes among the first half of the cohort (six strokes in 25 patients ¼ 24%), we started to adjust our procedural approach. This included a different type of cerebral perfusion during cardio pulmonary bypass procedures: Instead of using direct antegrade perfusion, which involves inserting a catheter directly into the carotid arteries and often led to the need to readjust such a catheter, we switched to axillary antegrade selective cerebral perfusion. By doing so, the catheter for cerebral perfusion was no longer in the main surgical field, permitting for more stable conditions of perfusion. Correspondingly, studies of open arch repair found axillary antegrade selective cerebral perfusion to lower the risk of neurologic complications.14,15 Also, as far as it was permitted by the case status, we revascularized the left subclavian artery whenever possible, trying to evade strokes caused by hypoperfusion of the vertebral arteries. While none of the said procedural adjustments was found to be a significant predictor of stroke, the rate of strokes among the second half of our cohort declined to 12% (three strokes in 25 patients), leading to the conclusion that our measures were effective. Still, a variety of possible other causes for stroke remains, ranging from detachment of thrombotic material or plaques by the stimulation with guide wires, catheters and stent devices, to the damage of vulnerable plaques during the procedure, causing postoperative thrombus formation. In addition, the length of surgery increases the risk of stroke, as demonstrated by the EUROSTAR registry.12
Reasons for technical failure In the present study, 5 (10%) of patients were affected by endoleak type I. This leakage in the aortic arch might have been caused by the types of stents being used in the present study, most of which were developed for the application in the descending thoracic aorta. However, the aortic arch warrants special requirements for the stent-grafts, such as increased flexibility and elasticity, due to the pronounced pulsation in this region. A stent-graft which does not adapt to the curvature of the aortic arch is likely to protrude at the lesser curvature of the aortic arch, hence forming a so-called bird’s beak and increasing the risk of collapse of the stent-graft or formation of an endoleak type I. In addition, in the present study a different diameter of the proximal and distal landing zones could be found frequently, while there were no stents available providing these specifications. Hence, further
16 stent-graft development is needed to decrease the rate of complications in this anatomically challenging area. The supra-aortic branches represent yet another challenge for the application of stent-grafts.6,7,16
Vascular 23(1)
5.
6.
Conclusions In severely ill patients with complex aortic diseases, hybrid therapy offers a treatment alternative to open aortic arch repair, hence accomplishing an opportunity to operate on patients otherwise deemed unfit for surgery. In the present study, we were able to achieve acceptable results in regard to mortality and technical success; however, related complications such as stroke remained high and call for further procedural and technical improvements, as well as careful patient selection. Hence, hybrid therapy of aortic arch pathologies should not replace open aortic repair but amplify the surgical armamentarium. Funding
7.
8.
9.
10.
11.
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. 12.
Conflict of interest None declared.
References 1. Milewski RK, Szeto WY, Pochettino A, et al. Have hybrid procedures replaced open aortic arch reconstruction in high-risk patients? A comparative study of elective open arch debranching with endovascular stent graft placement and conventional elective open total and distal aortic arch reconstruction. J Thorac Cardiovasc Surg 2010; 140: 590–597. 2. Ergin MA, Galla JD, Lansman s L, et al. Hypothermic circulatory arrest in operations on the thoracic aorta. Determinants of operative mortality and neurologic outcome. J Thorac Cardiovasc Surg 1994; 107: 788–797; discussion 797–799. 3. Sundt TM III, Orszulak TA, Cook DJ, et al. Improving results of open arch replacement. Ann Thorac Surg 2008; 86: 787–796; discussion 96. 4. Cao P, De Rango P, Czerny M, et al. Systematic review of clinical outcomes in hybrid procedures for aortic arch
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dissections and other arch diseases. J Thorac Cardiovasc Surg 2012; 144: 1286–1300,1300 e1–e2. Chaikof EL, Blankensteijn JD, Harris PL, et al. Reporting standards for endovascular aortic aneurysm repair. J Vasc Surg 2002; 35: 1048–1060. Ishimaru S. Endografting of the aortic arch. J Endovasc Ther 2004; 11(Suppl 2): II62–II71. Antoniou GA, Mireskandari M, Bicknell CD, et al. Hybrid repair of the aortic arch in patients with extensive aortic disease. Eur J Vasc Endovasc Surg 2010; 40: 715–721. Gelpi G, Vanelli P, Mangini A, et al. Hybrid aortic arch repair procedure: reinforcement of the aorta for a safe and durable landing zone. Eur J Vasc Endovasc Surg 2010; 40: 709–714. Melissano G, Civilini E, Bertoglio L, et al. Results of endografting of the aortic arch in different landing zones. Eur J Vasc Endovasc Surg 2007; 33: 561–566. Piffaretti G, Mariscalco G, Lomazzi C, et al. Predictive factors for endoleaks after thoracic aortic aneurysm endograft repair. J Thorac Cardiovasc Surg 2009; 138: 880–885. Tadakoshi M, Ishibashi H, Ishiguchi T, et al. Stent strut penetration during thoracic endovascular aortic repair: report of a case. Surg Today 2012; 42: 493–496. Buth J, Harris PL, Hobo R, et al. Neurologic complications associated with endovascular repair of thoracic aortic pathology: incidence and risk factors. A study from the European Collaborators on Stent/Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) registry. J Vasc Surg 2007; 46: 1103–1110; discussion 10–1. Gutsche JT, Cheung AT, McGarvey ML, et al. Risk factors for perioperative stroke after thoracic endovascular aortic repair. Ann Thorac Surg 2007; 84: 1195–1200; discussion 200. Jacobs MJ, de Mol BA and Veldman DJ. Aortic arch and proximal supraaortic arterial repair under continuous antegrade cerebral perfusion and moderate hypothermia. Cardiovasc Surg 2001; 9: 396–402. Yamashiro S, Kuniyoshi Y, Arakaki K, et al. Total arch replacement using bilateral axillary antegrade selective cerebral perfusion. Ann Thorac Cardiovasc Surg 2010; 16: 259–263. Canaud L, Hireche K, Berthet JP, et al. Endovascular repair of aortic arch lesions in high-risk patients or after previous aortic surgery: midterm results. J Thorac Cardiovasc Surg 2010; 140: 52–58.
Clinical outcomes in hybrid repair procedures for pathologies involving the aortic arch
Vascular 2015, Vol. 23(1) 9–16 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1708538114525608 vas.sagepub.com
Sebastian Zerwes1, Giesbert Leissner2, Yvonne Gosslau1, Rudolf Jakob1, Hans-Kees Bruijnen1, Frank Oertl3 and Klaus Woelfle1
Abstract Objective: Fifty patients with complex aortic disease, who received hybrid treatment of the aortic arch with supraaortic debranching and endovascular stent-graft repair, were evaluated in regard to events of primary (survival and technical success) and secondary (procedure-related complications) interest. Methods: The single-center study was conducted over an eight-year period from December 2004 to December 2012. Treated medical conditions included 23 aortic aneurysms (46%), 21 aortic dissections (42%), and six penetrating aortic ulcers (12%). Procedures were divided into groups of elective, urgent, and emergent. Results: Twenty-eight (56%) patients were operated electively, 15 (30%) urgently, and seven (14%) emergently. Sternotomy, cardiopulmonary bypass, and deep hypothermic circulatory arrest were required in 12 (24%) patients. The primary technical success rate was 86% and raised to 92% (n ¼ 46) of secondary technical success rate after therapy of three type I endoleaks. The 30-day mortality added up to 16.0%, and the mean time of survival was 49.3 months. In a total of eight (16%) patients, an endoleak occurred (five endoleaks type I, three endoleaks type II), while nine (18%) of patients suffered a perioperative stroke. Conclusions: In severely ill patients with complex aortic diseases, hybrid therapy may offer a promising alternative to conventional open repair.
Keywords Hybrid repair, aortic arch, debranching, clinical results, stroke, aortic dissection
Introduction The treatment of pathologies of the aortic arch remains to be a major challenge. Due to the fact that the open replacement of the aortic arch still requires hypothermic cardiac arrest, this procedure is affiliated with high rates of mortality and morbidity.1–3 Recently, so-called hybrid repair procedures have been pushed into the foreground as a therapeutic alternative to open repair. Those procedures seem to promise a less invasive treatment, as they combine less burdensome extra-anatomical bypasses with thoracic endovascular aortic repair (TEVAR), hence allowing for aortic arch repair in patients who are suboptimal candidates for open surgery. Since pathologies of the aortic arch are relatively rare, it is only now that results from larger studies and even systematic reviews of clinical outcomes in hybrid procedures are being published.4 However, randomized
study results, guidelines, and recommendations by societies of vascular surgery are still to be accomplished. The goal of the present study was the evaluation of the clinical outcomes in 50 patients who received hybrid repair of the aortic arch. In this study, the events of primary interest were survival and technical success; the events of secondary interest were procedure-related complications. 1
Department of Vascular surgery, Klinikum Augsburg, Germany Department of Radiology, Klinikum Augsburg, Germany 3 Department of Cardiac surgery, Klinikum Augsburg, Germany 2
Corresponding author: Sebastian Zerwes, Department of Vascular surgery, Klinikum Augsburg, Germany. Email: [email protected]
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Methods Patient population The study represents a case series study with retrospective analysis of prospectively collected non-randomized data. The single-center study was conducted at Klinikum Augsburg over an eight-year period from December 2004 to December 2012 and enrolled 50 patients with hybrid repair of complex aortic disease. The criteria for patient selection were based upon the comorbidities, and hence risk of surgery, of the patients, as well as the particular anatomy of the aortic arch. Treated medical conditions included 23 aortic aneurysms (46%; average aneurysm diameter 60 mm; three aneurysms associated with lusorian artery aneurysms), 21 aortic dissections (42%; thereof six (12%) Stanford type A and 15 (30%) Stanford type B), and six penetrating aortic ulcers (12%). Out of the 50 patients included in this study, 28 (56%) were operated electively, 15 (30%) urgently, and 7 (14%) emergently.
Procedural approach Preoperatively, all patients received a computed tomography (CT) scan of the aorta including supra-aortic
branches (0.75 mm collimation, recon layer thickness 1 mm). Subsequently, all images were digitally reconstructed (image processing) and the size of the stentgraft to be applied was measured using the program 3mensio Medical Imaging (3mensio Medical Imaging B.V., Bilthoven, the Netherlands). In order to assess the individual risk of surgery, all secondary diagnoses were gathered and can be found together with the demographic data in Table 1. As far as permitted by the case status, the patients received a lung function test, an evaluation of the pump function of the left ventricle using echocardiography, as well as a sonographic assessment of the carotid and subclavian arteries. Whether a procedure was performed single or double stage was individually decided within the multidisciplinary board, consisting of vascular and cardiac surgeons, as well as interventional radiologists. Among the factors taken into consideration were the age of the patient, comorbidities, size of the aneurysm, as well as the risk of rupture of the aneurysm. Dissection-related procedures were mostly performed single stage in order to control symptoms of organ hypoperfusion or other life-threatening conditions. All surgical interventions were carried out in operating rooms (ORs) equipped with a C-arm X-ray unit (Philips Pulsera, screen diagonal 31 cm). All procedures were performed under general anesthesia.
Table 1. Demographics, comorbidities and principal diagnoses.
Age Male gender History of tobacco use Diabetes Hypertension Hyperlipidemia COPD Renal insufficiency Myocardial infarction Coronary artery disease History of stroke History of TIA Abdominal aneurysm Abdominal aneurysm surgery Ascending aortic surgery Principal diagnosis Aneurysm Dissection Penetrating aortic ulcer
Total (n ¼ 50)
Elective (n ¼ 28)
Urgent (n ¼ 15)
69 36 (72%) 6 (12%) 8 (16%) 38 (76%) 18 (36%) 4 (8%) 19 (38%) 5 (10%) 11 (22%) 5 (10%) 3 (6%) 6 (12%) 4 (8%) 10 (20%)
66 18 (64%) 4 (14%) 5 (18%) 19 (68%) 10 (36%) 4 (14%) 11 (39%) 3 (11%) 6 (21%) 3 (11%) 2 (7%) 5 (18%) 4 (14%) 5 (18%)
76 12 (80%) 1 (7%) 2 (13%) 14 (93%) 5 (33%) 0 4 (27%) 1 (7%) 4 (27%) 1 (7%) 1 (7%) 0 0 3 (20%)
2
23 (46%) 21 (42%) 6 (12%)
18 (64%) 7 (25%) 3 (11%)
3 (20%) 10 (67%) 2 (13%)
2 (29%) 4 (57%) 1 (14%)
COPD: chronic obstructive pulmonary disease; TIA: transient ischemic attack.
Emergent (n ¼ 7)
6 1 1 5 3 4 1 1 1 1
p
72 (86%) (14%) (14%) (71%) (43%) 0 (57%) (14%) (14%) (14%) 0 (14%) 0 (29%)
0.85 >0.99 0.19 >0.99 0.25 0.4 >0.99 0.89 >0.99 >0.99 0.20 0.25 0.30
}
0.03
Zerwes et al. During all cases that took place in cooperation with cardiac surgery, near-infrared spectroscopy was used to monitor cerebral perfusion. In regard to the proximal landing zone, we required at least 20 mm of healthy aorta, in order to be able to safely deploy the stent-graft. Stent placement was either performed retrogradely via a femoral/iliac conduit access, or antegradely through the ascending aorta. In order to ensure central positioning, the unfolding of the stent-graft took place in short apnea and controlled hypotension. Additionally, adenosine-induced cardiac arrest was conducted for the proximal landing zones 0 and 1, to allow for undisturbed stent-graftrelease without the pulsatile pressure of the antegrade blood flow. All patients received a first postoperative CT-scan control; if possible, follow-up CT-scan controls (CT serial imaging) were performed after 6, 12, 24, and 36 months.
Definition of events of primary and secondary interest Events of primary and secondary interest were defined as proposed by the guidelines for endovascular procedures by the AdHoc Committee.5 Technical success was defined as successful aortic debranching combined with a stent-graft placement with secure proximal and distal anchorage, without the need of conversion to open surgery. The event ‘‘stroke’’ was defined as the continued existence of neurologic symptoms for over 24 h. Events of primary interest in our study were technical success, as well as survival of the patient. Events of secondary interest were determined as procedural complications (endoleaks, peripheral embolization, etc.).
Statistical analysis All patients who underwent diagnostic measures that required a patient consent also agreed that the collected data may be used for study purposes. All data were collected using a Microsoft Excel 2007 database. To statistically analyze the collected data, the program Statsdirect Version 2.7.8 (StatsDirect Ltd, Cheshire, UK) was applied. The comparison of dichotomous variables was performed through calculation of odds ratios. Nominal variables with multiple characteristics were analyzed with a contingency table using the Fisher–Freeman–Halton exact test. Due to the small number of patients, there was no sufficient data to perform a multivariate analysis in regard to the endpoint ‘‘perioperative stroke.’’
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Results Patient demographics and surgical procedures As indicated by the p values in Table 1, no significant differences of distribution in regard to the case status were found. However, the distribution of principal diagnosis was significant in regard to case status, as the majority of elective cases were aneurysms, while the majority of urgent and emergent cases were dissections. Penetrating ulcers were equally distributed among the groups. The median ASA score was 3 (range 2–4); 64% (n ¼ 32) of the procedures were performed single stage, 36% (n ¼ 18) double stage. Tables 2 and 3 display the implemented debranching techniques and the distribution of proximal landing zones according to the internationally used Ishimaru classification.6 We considered all debranchings involving a frozen elephant trunk as proximal landing zone 3, since the stent-graft is anatomically located in said zone. Table 4 provides detailed information about the procedures that were carried out in cooperation with cardiac surgeons. All said procedures involved at least the revascularization of the innominate artery and the left common carotid artery. In 43 (86%), a transfemoral access was used for stent placement, one (2%) were delivered via an iliac conduit, and 6 (12%) were delivered antegradely through the ascending aorta. The antegrade approach was only chosen when the femoral vessels were unsuitable as access-side due to massive calcification or if the iliac vessels showed extreme kinking, hence making it difficult to deliver a stent-graft. An average of 1.5 stent-grafts was implanted (range 1–4 stent-grafts). We used stent-grafts by GORE (n ¼ 4), Medtronic (n ¼ 15), Jotec (n ¼ 9), Cook (n ¼ 10), and Le Maitre (n ¼ 42). The median stent diameter was 36.5 mm, and the median length of the stented distance was 200 mm. Forty-four percent of cases (n ¼ 22) were performed in cooperation with cardiac surgeons.
Table 2. Debranching. Complete debranching (revascularization of IA, LCCA and LSA) Revascularization of IA and LCCA Revascularization of LCCA and LSA Revascularization of LCCA Revascularization LSA
6 16 11 6 11
IA: innominate artery; LCCA: left common carotid artery; LSA: left subclavian artery.
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Vascular 23(1) Table 3. Proximal landing zones. Proximal landing zone
Total (n ¼ 50)
Elective (n ¼ 28)
Urgent (n ¼ 15)
Emergent (n ¼ 7)
p
0 1 2 3
18 (36%) 17 (34%) 11 (22%) 4 (8%)
9 9 7 3
4 (27%) 6 (40%) 4 (27%) 1 (7%)
5 (71%) 2 (29%) 0 0
0.34
(32%) (32%) (25%) (11%)
}
Table 4. Procedures performed in cooperation with cardiac surgeons. #
Sex
Case status
Procedure
CPB
Cerebral perfusion
1 2
m m
Elective Elective
þ
Direct selective antegrade
3 4 5 6
m f f f
Elective Elective Elective Elective
7 8
m m
Urgent Emergent
9
m
Urgent
10 11
f m
Elective Elective
12 13
m f
Urgent Elective
14 15 16
f m m
Elective Urgent Emergent
17 18 19 20 21 22
m m f m m f
Urgent Elective Elective Emergent Emergent Emergent
Revascularization of IA and LCCA Revascularization of IA and LCCA, FET, aortic valve repair Revascularization of IA and LCCA, FET Revascularization of IA and LCCA Revascularization of IA and LCCA Revascularization of IA and LCCA, replacement of ascending aorta and aortic arch (partial) Revascularization of IA and LCCA, FET Revascularization of IA and LCCA, replacement of ascending aorta and aortic arch (partial) Revascularization of IA and LCCA, replacement of ascending aorta and aortic arch (partial) Revascularization of IA and LCCA Revascularization of IA and LCCA, aortic valve repair, replacement of ascending aorta Revascularization of IA and LCCA Revascularization of IA and LCCA, replacement of ascending aorta Revascularization of IA and LCCA, FET Revascularization of IA and LCCA , CABG Revascularization of IA and LCCA, replacement of ascending aorta Complete debranching Complete debranching Complete debranching, CABG Complete debranching Complete debranching Complete debranching, aortic valve repair, replacement of ascending aorta and aortic arch (partial)
þ þ
Direct selective antegrade
þ þ
None Direct selective antegrade
þ
Direct selective antegrade
Direct selective antegrade
þ
None
þ þ þ
Axillary antegrade selective Axillary antegrade selective Axillary antegrade selective
þ þ
Axillary antegrade selective
Axillary antegrade selective
CABG: coronary artery bypass graft; CBP: cardio pulmonary bypass; f: female; FET: frozen elephant trunk; IA: innominate artery; LCCA: left common carotid artery; m: male.
Technical success In our study, eight patients (16%) suffered from endoleaks type I or II (5), one (2%) from intraoperative death, and one (2%) died within 24 h of surgery. No
conversion to open surgery, stent fracture, or stent migration occurred. Hence, the primary technical success rate was 86% and raised to 92% after successful therapy of three endoleaks.
Zerwes et al.
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Table 5. Postoperative outcomes: technical success and complications.
Primary technical success Secondary technical success Endoleak Type 1/thereof treated Endoleak Type 2/thereof treated Intraoperative death 30-day mortality Stroke Paraplegia Late-onset endoleak Clotting of debranching bypass Peripheral embolization Stent-associated hemorrhage
Total (n ¼ 50)
Elective (n ¼ 28)
Urgent (n ¼ 15)
Emergent (n ¼ 7)
p
43 (86%) 46 (92%) 5/3 (10%/6%) 3/1 (6%/2%) 1 (2%) 8 (16%) 9 (18%) 1 (2%) 0 3 (6%) 1 (2%) 1 (2%)
26 (93%) 27 (96%) 1/1 (4%/4%) 3/1 (11%/4%) 0 3 (11%) 5 (18%) 1 (4%) 0 2 (7%) 1 (4%) 1 (4%)
11 (73%) 12 (80%) 3/1 (20%/7%) 0/0 0 3 (20%) 4 (27%) 0 0 1 (7%) 0 0
5 (71%) 6 (86%) 1/1 (14%/14%) 0/0 1 (14%) 2 (29%) 0 0 0 0 0 0
0.15 0.15 0.15 0.71 0.14 0.43 0.45 >0.99 >0.99 >0.99 >0.99
Survival Taking into account the one intraoperative death and the one death within 24 h of surgery, 30-day mortality added up to 16% (n ¼ 8). Further details can be found in Table 5. The mean time of follow-up was 49 months (maximum 62 months), while the Kaplan–Meier estimates for survival after 1, 6, 12, 24, and 60 months were 84%, 81%, 81%, 70%, and 70%, respectively (Figure 1).
Complications An overview of all complications is shown in Table 5.
Endoleaks As stated above, a total of eight (16%) endoleaks was found in the first postoperative CT-scan control, five (10%) of which were endoleaks type I, while three (6%) corresponded to endoleaks type II. In the endoleak type I group, three of the five endoleaks were treated. Thereof two were endoleaks type Ia and received interventional coiling, while one was an endoleak type Ib and was treated by a stent extension. The remaining two endoleaks were only observed due to limited treatment options in regard to vascular anatomy. However, in the following CT controls, one had not increase in size, while the other had even regressed in size. In the endoleak type II group, one of three endoleaks was treated by interventional coiling of the lusorian artery. The remaining two endoleaks were only observed: One declined over the course of observation spontaneously, the other one did not show any progression of size during follow-up.
Figure 1. Survival analysis (including patients at risk) using the Kaplan–Meier-method.
Clotting of the debranching bypass Three patients (6%) suffered from clotting of the carotid–subclavian bypass. Thereof two were treated with a bypass revision due to stroke. The third patient did not receive a revision of the clotted bypass since he was neurologically stabile.
Cerebral and spinal complications A total of nine patients (18%) suffered an ischemic stroke, of which two (4%) were embolic, while seven (14%) were due to hypoperfusion. No intracranial hemorrhage occurred. The three (6%) patients with clotting of the debranching bypass were all among the seven (14%) strokes due to hypoperfusion. In the group of embolic strokes, a CT scan confirmed cerebral
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Table 6. Predictive factors for stroke (univariate analysis: odds ratio).
Risk factor Debranching including reinsertion of at least IA and LCCA LSA covered and not revascularized Involvement of cardiac surgery required CPB Age > median Renal insufficiency
Odds ratio (95% confidence interval) 1.02 (0,24–4,37) 3.13 1.02 1.55 1.31 0.78
(0,68–14,31) (0,24–4,37) (0,33–7,37) (0,30–5,60) (0,17–3,58)
CPB: cardio pulmonary bypass; IA: innominate artery; LCCA: left common carotid artery; LSA: left subclavian artery.
initial renal function, while the other two (2%) died from cerebral complications. One patient, who underwent tracheotomy during her intensive care unit stay, developed an infection of the debranching bypass of both carotids: She was conservatively treated with vacuum seal therapy and antibiotics and fully recovered. One patient with an acute aortic dissection hemorrhaged perioperatively due to an aortic wall erosion caused by baresprings of the stent. The baresprings of the proximal end of the stent-graft had caused bleeding of the aortic wall in the region of the anastomosis of the debranching bypass graft. The patient died shortly after surgery.
Hypoperfusion of the left arm Table 7. Predictive factors for stroke (univariate analysis: Fisher-Freeman-Halton exact). Risk factor Urgency (elective-urgent-emergent) Diagnosis (aneurysm-dissection-PAU) Covered aortic zones including zone 0–4 (Ishimaru)
Fisher–Freeman– Halton exact 0.45 0.6 0.06
PAU: penetrating aortic ulcer.
embolisms. Tables 6 and 7 show the univariate analysis of predictive factors for stroke. One patient suffered from spinal cord ischemia, which manifested itself as a paralysis of the left leg and vertigo. Since both symptoms improved during the in-hospital stay, the patient did not receive an additional intervention.
Peripheral embolization and other complications One patient (2%) developed multiple peripheral embolizations leading to right leg ischemia, embolic small bowl ischemia, and multiple organ infarctions (liver, kidney, and spleen), which lead to the patient’s death four days postoperatively. Two patients (4%) suffered from a myocardial infarction postoperatively, one of whom subsequently was treated with coronary artery bypass grafts. The other patient developed a pericardial effusion which was drained operatively. One patient (2%) experienced a multiorgan failure with respiratory insufficiency, leading to the patient’s death. Acute renal failure occurred in four patients (8%). Thereof two (2%) fully recovered and regained their
None of the 28 (56%) patients who received a revascularization of the left subclavian artery developed a symptomatic hypoperfusion of the left arm. Out of the 22 (44%) patients who did not get their subclavian artery revascularized, one (2%) patient developed a steal syndrome, while another one suffered from a symptomatic hypoperfusion of the left arm.
Discussion Although open surgical repair is considered by many as the treatment of choice for pathologies involving the aortic arch in low-risk patients, such invasive surgery is associated with significant in-hospital mortality rates as reported by many studies.1–3 In comparison, hybrid repair of the aortic arch with supra-aortic debranching prior to stent-graft deployment has the advantage of providing reduced invasiveness and hence accomplishing an opportunity to operate on patients otherwise deemed unfit for surgery. Nevertheless, apart from the remaining difficulties with the application of endovascular devices in this anatomically challenging area, this relatively new technique still requires validation as a treatment option.4,7 The present study reports our outcomes of 50 patients who underwent hybrid repair. Taking into account previously published studies, it represents a rather large series.4 The majority of our cohort were high-risk patients with significant co-morbidities. For instance, 13 (26%) of patients had had previous cardiac or vascular surgery, 42 (84%) had one or more cardiac risk factors, and eight (16%) had had a neurologic event. In addition, the involvement of the cardiac surgery department was needed in 22 (44%) cases, which makes a comparison of outcomes of other studies, which tend to have lower cardiac surgery participation, difficult.
Zerwes et al.
Stent-associated complications The most common stent-associated complications were endoleaks. The majority of studies incorporate only the occurrence of endoleaks type I and III, which require primary therapy and are important for technical success. The incidence of endoleaks varies from 0 to 30%, with some authors reporting increased rates of endoleaks the more central the proximal landing zones and the more stents being used.5,6,8 In the present study, we detected in the first postoperative control in 5 (10%) an endoleak type I, thereof 3 (6%) were treated. All treated endoleaks were eliminated. No endoleaks type III occurred; furthermore, no late-onset endoleaks were observed. Compared to the results of other reports, the number of endoleaks in the present study is relatively small. One of our strategies to avoid endoleaks was to create an adequate proximal landing zone of at least 20 mm, as postulated by many other authors.9,10 Using an average landing zone of 38 mm, Gelpi et al. report an endoleak rate of 0%. In order to achieve that, they favor a complete debranching.8 Whether the benefits of a low endoleaks rate outweigh the surgical risks of complete debranching seems at least worthy of discussion. Despite a low incidence of endoleaks for total debranching, Melissano et al.9 reported an increased risk for neurologic complications. We consider a proximal landing of 20 mm to be sufficient, since acceptable rates of endoleaks can be accomplished while avoiding the risks of complete debranching. Regular CT-scan controls warrant adequate safety. In the early phase of our study, one patient with an acute aortic dissection hemorrhaged perioperatively due to an aortic wall erosion caused by baresprings of the stent. As described before, the baresprings of the proximal end of the stent-graft had caused bleeding of the aortic wall in the region of the anastomosis of the debranching bypass graft. While this stent with baresprings was certainly not the best therapeutic option for this patient, it was the only one at hand at that time. Tadakoshi et al.11 describe a similar case in which the baresprings also caused bleeding of the aortic wall. We stopped using stents with baresprings in zones close to debranching bypasses ever since.
Neurologic complications Ischemic stroke is an important complication after TEVAR. The more central the pathology of the thoracic aorta, the higher the risk of stroke.12,13 Overall, the present study showed an increased rate of strokes, which affected 9 (18%) of patients. Other studies report perioperative stroke rates after hybrid repair, ranging from 0.8% to 25.0% with a pooled event ratio of 6.9%.4 In our study, two-thirds of the strokes affected the first half of the patient population, while only one-third of the
15 strokes affected the latter cohort. Thus, the rate of strokes declined over the course of time. While this is concurrent with the findings of Cao et al.4, stating that an increased caseload lowered the risk of neurologic complications, this effect is influenced by different factors. When we noticed the high rate of strokes among the first half of the cohort (six strokes in 25 patients ¼ 24%), we started to adjust our procedural approach. This included a different type of cerebral perfusion during cardio pulmonary bypass procedures: Instead of using direct antegrade perfusion, which involves inserting a catheter directly into the carotid arteries and often led to the need to readjust such a catheter, we switched to axillary antegrade selective cerebral perfusion. By doing so, the catheter for cerebral perfusion was no longer in the main surgical field, permitting for more stable conditions of perfusion. Correspondingly, studies of open arch repair found axillary antegrade selective cerebral perfusion to lower the risk of neurologic complications.14,15 Also, as far as it was permitted by the case status, we revascularized the left subclavian artery whenever possible, trying to evade strokes caused by hypoperfusion of the vertebral arteries. While none of the said procedural adjustments was found to be a significant predictor of stroke, the rate of strokes among the second half of our cohort declined to 12% (three strokes in 25 patients), leading to the conclusion that our measures were effective. Still, a variety of possible other causes for stroke remains, ranging from detachment of thrombotic material or plaques by the stimulation with guide wires, catheters and stent devices, to the damage of vulnerable plaques during the procedure, causing postoperative thrombus formation. In addition, the length of surgery increases the risk of stroke, as demonstrated by the EUROSTAR registry.12
Reasons for technical failure In the present study, 5 (10%) of patients were affected by endoleak type I. This leakage in the aortic arch might have been caused by the types of stents being used in the present study, most of which were developed for the application in the descending thoracic aorta. However, the aortic arch warrants special requirements for the stent-grafts, such as increased flexibility and elasticity, due to the pronounced pulsation in this region. A stent-graft which does not adapt to the curvature of the aortic arch is likely to protrude at the lesser curvature of the aortic arch, hence forming a so-called bird’s beak and increasing the risk of collapse of the stent-graft or formation of an endoleak type I. In addition, in the present study a different diameter of the proximal and distal landing zones could be found frequently, while there were no stents available providing these specifications. Hence, further
16 stent-graft development is needed to decrease the rate of complications in this anatomically challenging area. The supra-aortic branches represent yet another challenge for the application of stent-grafts.6,7,16
Vascular 23(1)
5.
6.
Conclusions In severely ill patients with complex aortic diseases, hybrid therapy offers a treatment alternative to open aortic arch repair, hence accomplishing an opportunity to operate on patients otherwise deemed unfit for surgery. In the present study, we were able to achieve acceptable results in regard to mortality and technical success; however, related complications such as stroke remained high and call for further procedural and technical improvements, as well as careful patient selection. Hence, hybrid therapy of aortic arch pathologies should not replace open aortic repair but amplify the surgical armamentarium. Funding
7.
8.
9.
10.
11.
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. 12.
Conflict of interest None declared.
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